Midwest

The Midwest is home to over 60 million people, and its active economy represents 18% of the U.S. gross domestic product.1 The region is probably best known for agricultural production. Increases in growing-season temperature in the Midwest are projected to be the largest contributing factor to declines in the productivity of U.S. agriculture.2 Increases in humidity in spring through mid-century3,4 are expected to increase rainfall, which will increase the potential for soil erosion5,6 and further reduce planting-season workdays due to waterlogged soil.7

Forests are a defining characteristic of many landscapes within the Midwest, covering more than 91 million acres. However, a changing climate, including an increased frequency of late-growing-season drought conditions, is worsening the effects of invasive species, insect pests, and plant disease as trees experience periodic moisture stress. Impacts from human activities, such as logging, fire suppression, and agricultural expansion, have lowered the diversity of the Midwest’s forests from the pre-Euro-American settlement period. Natural resource managers are taking steps to address these issues by increasing the diversity of trees and introducing species suitable for a changing climate.8

The Great Lakes play a central role in the Midwest and provide an abundant freshwater resource for water supplies, industry, shipping, fishing, and recreation, as well as a rich and diverse ecosystem. These important ecosystems are under stress from pollution, nutrient and sediment inputs from agricultural systems, and invasive species.9,10 Lake surface temperatures are increasing,11,12 lake ice cover is declining,12,13,14 the seasonal stratification of temperatures in the lakes is occurring earlier in the year,15 and summer evaporation rates are increasing.13,16 Increasing storm impacts and declines in coastal water quality can put coastal communities at risk. While several coastal communities have expressed willingness to integrate climate action into planning efforts, access to useful climate information and limited human and financial resources constrain municipal action.

Land conversion, and a wide range of other stressors, has already greatly reduced biodiversity in many of the region’s prairies, wetlands, forests, and freshwater systems. Species are already responding to changes that have occurred over the last several decades,17,18,19 and rapid climate change over the next century is expected to cause or further amplify stress in many species and ecological systems in the Midwest.20,21,22 The loss of species and the degradation of ecosystems have the potential to reduce or eliminate essential ecological services such as flood control, water purification, and crop pollination, thus reducing the potential for society to successfully adapt to ongoing changes. However, understanding these relationships also highlights important climate adaptation strategies. For example, restoring systems like wetlands and forested floodplains and implementing agricultural best management strategies that increase vegetative cover (cover crops and riparian buffers) can help reduce flooding risks and protect water quality.23,24,25

Midwestern populations are already experiencing adverse health impacts from climate change, and these impacts are expected to worsen in the future.26,27 In the absence of mitigation, ground-level ozone concentrations are projected to increase across most of the Midwest, resulting in an additional 200–550 premature deaths in the region per year by 2050.28 Exposure to high temperatures impacts workers’ health, safety, and productivity.29 Currently, days over 100°F in Chicago are rare. However, they could become increasingly more common by late century in both the lower and higher scenarios (RCP4.5 and RCP8.5).

The Midwest also has vibrant manufacturing, retail, recreation/tourism, and service sectors. The region’s highways, railroads, airports, and navigable rivers are major modes for commerce activity. Increasing precipitation, especially heavy rain events, has increased the overall flood risk, causing disruption to transportation and damage to property and infrastructure. Increasing use of green infrastructure (including nature-based approaches, such as wetland restoration, and innovations like permeable pavements) and better engineering practices are beginning to address these issues.

Citizens and stakeholders value their health and the well-being of their communities—all of which are at risk from increased flooding, increased heat, and lower air and water quality under a changing climate.30,31 To better prevent and respond to these impacts, scholars and practitioners highlight the need to engage in risk-driven approaches that not only focus on assessing vulnerabilities but also include effective planning and implementation of adaptation options.32

Conservation Practices Reduce Impact of Heavy Rains

Two photos are shown; one is inset in the bottom right corner of the other. The main photo shows an aerial view of a dark green soybean field, with lighter green, semicircular strips of native prairie vegetation integrated at regular intervals. The prairie strip vegetation shows some yellow flowering plants. The inset photo shows a closeup view of the native prairie vegetation, depicting yellow flowers in the center of the photo and darker green row crops on the left and right margins.

Integrating strips of native prairie vegetation into row crops has been shown to reduce sediment and nutrient loss from fields, as well as improve biodiversity and the delivery of ecosystem services.33 Iowa State University’s STRIPS program is actively conducting research into this agricultural conservation practice.34 The inset shows a close-up example of a prairie vegetation strip. From Figure 21.2 (Photo credits: [main photo] Lynn Betts, [inset] Farnaz Kordbacheh.)

Photograph showing two men standing on a forest floor. There are shrubs, ferns, dead tree limbs, and uprooted tree stumps around them. One man digs a hole with a shovel while the other stoops down to plant a tree seedling.

The photo shows Menominee Tribal Enterprises staff creating opportunity from adversity by replanting a forest opening caused by oak wilt disease with a diverse array of tree and understory plant species that are expected to fare better under future climate conditions. From Figure 21.4 (Photo credit: Kristen Schmitt).